Bacteriophages Concept and Applications: A Review on Phage Therapy

The nature of phages was a matter of dispute, which was resolved in 1940, and it was continued to develop their activity and application in the Soviet Union and Eastern Europe. Bacteriophages were first employed in 1919 to treat bacterial illnesses caused by Citrobacter, Enterobacter, and Pseudomonas. Bacteriophages range in complexity from simple spherical viruses with genome sizes of less than 5 kbp to complicated viruses with genome sizes surpassing 280 kbp. They have two significant parts, head and tail, and are made up of numerous copies of more than 40 distinct proteins. Bacteriophages have been demonstrated to bind with receptors in the walls of both gram-positive and gram-negative bacteria, ranging from peptide sequences to polysaccharide moieties. Depending on the type of phage and the physiological state of the bacterium, the life cycle may diverge into the lytic cycle or lysogenic cycle. Lytic-lysogenic switch depends on a variety of inducing factors. Bacteriophage therapy can be administered via several routes, but parenteral routes are the most effective. Auto-dosing, single-dose potential, lack of cross-resistance with antibiotics, etc., are several advantages of phage therapy over antibiotic treatment. Bacteriophages are attracting much attention because of their potential advantages and wide applications as antibacterial agents, diagnostic technologies, phage-based products, and biocontrol agents. They also have several applications in the food industry, agriculture/crop, farm animal and bee protection, environmental, and biosensor development.